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Diagnosing gas-like smell coming from basement

I first ran into this "gas smell" problem when the Army sent me to the desert (Kuwait). Good thing, too. Saved me from calling the "dumb" gas company or an HVAC tech when it happened in my 3-story townhouse in VA.

When the p-trap in the basement floor drain goes dry, it allows sewer gas to pass into the house. Pouring a gallon or more of water down the drain stops the smell (until the next time it dries out).

Why is it that techs (gas company, HVAC company) can come out to investigate the "smell of gas", not find any "leak", and not even suggest pouring water down the floor drain? It happened to a friend of mine in VA and I couldn't believe it!

I first ran into this "gas smell" problem when the Army sent me to the desert (Kuwait). Good thing, too. Saved me from calling the "dumb" gas company or an HVAC tech when it happened in my 3-story townhouse in VA.

When the p-trap in the basement floor drain goes dry, it allows sewer gas to pass into the house. Pouring a gallon or more of water down the drain stops the smell (until the next time it dries out).

Why is it that techs (gas company, HVAC company) can come out to investigate the "smell of gas", not find any "leak", and not even suggest pouring water down the floor drain? It happened to a friend of mine in VA and I couldn't believe it!

because when you say "gas" their thinking natural gas, not sewer gas.

"Better tell the sandman to stay away, because we're gonna be workin on this one all night."

"Dude, you need more than 2 wires to a condenser to run a 2 stage heatpump."

I'm thinking short-sighted "not my problem" syndrome, i.e., no leak, so "your" smell is not "my" company's problem... pay someone else to figure it out and don't waste my time. Or is there simply a training deficiency among service providers in the US?

While a licensed plumber MIGHT consider a dry trap in a basement floor drain, in residential applications all floor drains are not created equal. For example, in my area it's not uncommon to find a floor drain with no trap that terminates in a sump pump well, with the floor drain above the water line, thus creating an air gap so no trap is required. A natural gas tech is unlikely to think of plumbing issues, unless he's run into the situation before. In your case, you've had prior experience that gave you some insight as to the potential problem. Normally, again in our area, floor drains that are tied into the plumbing drains/sewer pipe are trapped but those traps also must be kept wet. That's usually accomplished by actually using the drain, such as floor washing. Having a drain tied into the plumbing makes little sense otherwise, IMO. If I were you I'd post a not somewhere that tells all there's a floor drain with a trap that needs to be kept primed. (There are automatic trap primers available that will shoot some water into the trap each time another faucet in the house is closed if you can't remember to otherwise keep it primed.

If YOU want change, YOU have to first change.

If you are waiting for the 'other guy' to change first, just remember, you're the 'other guy's' other guy. To continue to expect real change when you keep acting the same way as always, is folly. Won't happen. Real change will only happen when a majority of the people change the way they vote!

tech is unlikely to think of plumbing issues, unless he's run into the situation before.

floor drains that are tied into the plumbing drains/sewer pipe are trapped but those traps also must be kept wet. That's usually accomplished by actually using the drain, such as floor washing. Having a drain tied into the plumbing makes little sense otherwise, IMO.

In my situation, the floor drain was tied to the plumbing drain (no sump pump required) and provided drainage for the A/C condensate drain line positioned directly above it. A/C was in the unfinished laundry room and I never needed to "wash the floor". In the winter, when the A/C was not running, the p-trap would dry out. I sold the house and probably should have left a note or advised the buyer to keep the drain wet. Oh well, I'm in Florida now and we don't have basements!

I'm thinking short-sighted "not my problem" syndrome, i.e., no leak, so "your" smell is not "my" company's problem... pay someone else to figure it out and don't waste my time. Or is there simply a training deficiency among service providers in the US?

More like "I can't find the natural gas leak you told me about, using a leak detector."
Especially if the tech can't smell the smell your talking about. Most techs, if they knew that you meant sewer gas, would fix the problem.
But if you say natural gas, and they can't smell the sewer gas, they wouldn't know to look for it.
It's like telling a mechanic to fix your truck, and you got upset because he didn't fix your honda civic.

Most techs, if they knew that you meant sewer gas, would fix the problem.
But if you say natural gas, and they can't smell the sewer gas, they wouldn't know to look for it.

Some of our smelling senses aren't exactly prestine.

I'm not ragging on your lack of olfactory prowess. LOL

But, if the homeowner knew it smelled like sewer gas, they'd probably call a plumber! To the homeowner's untrained nose, if it smells like gas or exhaust fumes, it could be anything... from a natural gas leak to a freon leak to carbon monoxide to jet fuel dumped from a plane flying overhead or exhaust from a neighbors lawn mower. Point is, why should the homeowner have to suffer a process of elimination by calling all manner of specialists when the residential service techs (gas company, HVAC company) that deal in leaks everyday could be trained to suggest the floor drain as a possible source of the smell. Just sayin', it would be too easy.

But, if the homeowner knew it smelled like sewer gas, they'd probably call a plumber! To the homeowner's untrained nose, if it smells like gas or exhaust fumes, it could be anything... from a natural gas leak to a freon leak to carbon monoxide to jet fuel dumped from a plane flying overhead or exhaust from a neighbors lawn mower. Point is, why should the homeowner have to suffer a process of elimination by calling all manner of specialists when the residential service techs (gas company, HVAC company) that deal in leaks everyday could be trained to suggest the floor drain as a possible source of the smell. Just sayin', it would be too easy.

I've been on this call a number of times.

"It smells like <insert something foul> in my office."

I always consider dry trap as a cause as it is pretty common, particularly in springtime after units have been off all winter.

But, if the homeowner knew it smelled like sewer gas, they'd probably call a plumber! To the homeowner's untrained nose, if it smells like gas or exhaust fumes, it could be anything... from a natural gas leak to a freon leak to carbon monoxide to jet fuel dumped from a plane flying overhead or exhaust from a neighbors lawn mower. Point is, why should the homeowner have to suffer a process of elimination by calling all manner of specialists when the residential service techs (gas company, HVAC company) that deal in leaks everyday could be trained to suggest the floor drain as a possible source of the smell. Just sayin', it would be too easy.

By all means, I don't disagree with you. As a general rule of thumb, if you called us, unless it's something we can't safely, or legally do, we take care of it.

I took this specific situation as:
Homeowner is out of town, someone else calls him to say something smells like gas.
Homeowner calls tech about gas smell, tech looks and can't find gas leak.
I guess I assumed at this point, that the tech couldn't get ahold of the homeowner, so he left an invoice.

maybe I'm just naive, but I can't imagine a tech walking out without talking to the homeowner about the whens wheres and hows.

"Better tell the sandman to stay away, because we're gonna be workin on this one all night."

"Dude, you need more than 2 wires to a condenser to run a 2 stage heatpump."

I am confused as to the premise of your post. Some companies are hvac companies that primarily deal in heating, ventilation, and air conditioning. Other companies are hvac/plumbing/electrical (jack of all master of none). Perhaps you called the wrong type of company or called one that is not qualified/experienced?

I am confused as to the premise of your post. Some companies are hvac companies that primarily deal in heating, ventilation, and air conditioning. Other companies are hvac/plumbing/electrical (jack of all master of none). Perhaps you called the wrong type of company or called one that is not qualified/experienced?

Here's the premise -

In the spring, homeowner smells a foul odor in the rooms above the utility space in the basement, and at the top of the basement stairs, Has no idea what it is, but fears potentially dangerous combustible fumes (i.e., "gas") coming from somewhere and getting into the ventilation system. Homeowner calls the gas company... they check for gas leaks, find none and leave... this "smell" is not the gas company's problem. Homeowner calls the HVAC service tech... they check for freon leaks, find none and leave...this "smell" is not the HVAC contractor's problem. Homeowner sniffs around the sinks, toilets and showers in the house and doesn't smell anything, so doesn't call a plumber.

Homeowner lives with the odor for another month and it goes away once the A/C is turned on... forgets about it until the smell comes back the following spring. Homeowner complains to neighbor about smell and describes how gas company couldn't find a leak, HVAC company couldn't find a leak, so what the hell is it?

Neighbor suggests dry p-trap in floor drain in basement equipment room and recommends pouring water into the drain. Problem solved, but neighbor is pissed as to why neither the gas company or the HVAC company suggested that. Aren't they supposed to have "whole house" knowledge in the neighborhoods they service?

Like I said... not my problem anymore. I live in Florida now and we don't have basements or floor drains.